/*  Statement: http://acmp.ru/?main=task&id_task=143
   Verdict: Accepted
*/
import java.math.*;
import java.util.*;
import java.io.*;
 
public class Main {
        
    public BufferedReader in;
    public StringTokenizer stoken = new StringTokenizer("");
    public PrintWriter out;
        
    public static void main(String[] args) throws IOException {
        new Main();
    }
 
    Main() throws IOException{
        in = new BufferedReader(new FileReader("input.txt")); 
        out = new PrintWriter(new FileWriter("output.txt"));
        BigInteger m  = new BigInteger(in.readLine());
        BigInteger n = new BigInteger(in.readLine());
        m = m.subtract(n);
        out.println(m.toString());
        out.close();
    }
    
    private int nextInt() throws NumberFormatException, IOException {
        return Integer.parseInt(nextString());
    }

    private String nextString() throws IOException {
        while(!stoken.hasMoreTokens()){
            String st = in.readLine();
            stoken = new StringTokenizer(st);
        }
        return stoken.nextToken();
    }
    
} 
